Rain gages data represents limited spatial coverage, especially in rugged terrains like Lebanon. Other precipitation data sources are the developing satellite and radar technologies. In this study, Tropical Rain Measurement Mission (TRMM) monthly rainfall data of 18 years (1998-2014 and 2017) was used to understand monthly and yearly precipitation spatial distribution overall Lebanon. Topographic effect of rainfall spatial distribution was investigated in comparison to Plassard’s map of 1971. The annual precipitation over the country ranged between 850 mm and 200 mm that differs than the existing historical map. The maximum rainfall rate decreased by about 700 mm between the derived TRMM rainfall map and Plassard’s one. Spatial distribution of maximum precipitation rates does not coincide between maps. TRMM map of elevated terrains did not show similar trends of rainfall distribution as Plassard’s. Pixels (Lebanon was divided into 27 pixels) of lower rainfall rates was found toward the eastern side of Lebanon, in contrast to Plassard’s results. Anti-Lebanon did not show an increase in precipitation in accordance to altitude. Spatial variability of precipitation was about 50 mm between pixels which reveals the importance of considering topography while implemented rain gages as observation points. TRMM and satellite rainfall data aid in investigating complete spatial distribution of rainfall over continuous periods. Accumulating knowledge of spatial rainfall distribution on timely basis will lead to better future modelling on floods and drought conditions in Lebanon.
References
[1]
Villarini, G., Mandapaka, V.P., Krajewski, W.F. and Moore, R.J. (2008) Rainfall and Sampling Uncertainties: A Rain Gauge Perspective. Journal of Geophysical Research, 113, D11102. https://doi.org/10.1029/2007JD009214
[2]
Arnaud, P., Bouvier, C., Cisneros, L. and Dominguez, R. (2002) Influence of Rainfall Spatial Variability on Flood Prediction. Journal of Hydrology, 260, 216-230.
https://doi.org/10.1016/S0022-1694(01)00611-4
[3]
Shaban, A., Robinson, C. and El-Baz, F. (2009) Using MODIS Images and TRMM Data to Correlate Rainfall Peaks and Water Discharges from the Lebanese Coastal Rivers. Journal of Resources and Protection, 4, 227-236.
https://doi.org/10.4236/jwarp.2009.14028
[4]
Yates, D., Purkey, D., Sieber, J., Huber-Lee, A., Galbraith, H., West, J., Herrod-Julius, S., Young, C., Joyce, B. and Rayej, M. (2009) Climate Driven Water Resources Model of the Sacramento Basin, California. Journal of Water Resources Planning and Management, 135, 303-313.
https://doi.org/10.1061/(ASCE)0733-9496(2009)135:5(303)
[5]
Cristiano, E., ten Veldhuis, M.C. and van de Giesen, N. (2017) Spatial and Temporal Variability of Rainfall and Their Effects on Hydrological Response in Urban Areas—A Review. Hydrology and Earth System Sciences, 21, 3859-3878.
https://doi.org/10.5194/hess-21-3859-2017
[6]
New, M., Todd, M., Hulme, M. and Jones, P. (2001) Precipitation Measurements and Trends in the Twentieth Century. International Journal of Climatology, 21, 1899-1922.
https://doi.org/10.1002/joc.680
[7]
Fischer, T., Zeng, Y. and Fraedrich, K. (2016) Evaluation of TRMM 3B43 Precipitation Data for Drought Monitoring in Jiangsu Province, China. Water, 8, 221.
https://doi.org/10.3390/w8060221
[8]
Chandrasekar, V., Srinivasa Ramanujam, K., Chen, H., Le, M. and Alqudah, A. (2014) Rainfall Estimation from Spaceborne and Ground Based Radars Using Neural Networks. IEEE Geoscience and Remote Sensing Symposium, Quebec City, 13-18 July 2014, 4966-4969. https://doi.org/10.1109/IGARSS.2014.6947610
https://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6919813
[9]
Plassard, J. (1971) Carte pluviométrique du Liban á l'échelle 1/200,000. Ministère des travaux publics. Direction Générale de l’Aviation Civile.
[10]
Huffman, G.J., Adler, R.F., Rudolf, B., Schneider, U. and Keehn, P.R. (1995) Global Precipitation Estimates Based on a Technique for Combining Satellite-Based Estimates, Rain Gauge Analysis, and NWP Model Precipitation Information. Journal of Climate, 8, 1284-1295.
https://doi.org/10.1175/1520-0442(1995)008<1284:GPEBOA>2.0.CO;2
[11]
Jomaa, I., Skaf, S., Massaad, R. and Elhaj, N. (2011) Variabilité climatique au Liban. Actes de Coloque; Environnement et Gestion Durable de Ecosystemes Naturels au Moyen-Orient. 18-20 April, 2011, AUF, Beirut.
[12]
Chokngamwong, R. and Chiu, L.S. (2008) Thailand Daily Rainfall and Comparison with TRMM Products. Journal of Hydrometeorology, 9, 256-266.
https://doi.org/10.1175/2007JHM876.1
